One of known home systems provided with solar cells is an invention described in Patent Literature 1, for example. Patent Literature 1 describes about the following operation. The home system calculates an amount of photovoltaic electricity predicted and an amount of charging electricity predicted for a vehicle rechargeable battery and supplies the photovoltaic electricity to the vehicle rechargeable battery if the rechargeable battery needs to be charged. When the amount of photovoltaic electricity predicted is larger than the amount of charge predicted, the home system supplies the surplus electricity to house loads. When the amount of photovoltaic power predicted is larger than the sum of the amount of charge predicted and the house loads, the home system supplies the surplus electricity to a house-side rechargeable battery. When there is still surplus electricity, the surplus electricity can be sold.
However, the solar cells are not always generating enough electricity when the electric vehicle is connected to a charger. Accordingly, the vehicle battery is sometimes charged from the grid power. In order to avoid charging from the grid power, in Patent Literature 1, the rechargeable battery is provided for the house. The house-side rechargeable battery is temporarily charged from electricity generated by the solar cells, and then the rechargeable battery of the electric vehicle connected to the charger is charged from electricity discharged from the house rechargeable battery.
However, in the method of providing a rechargeable battery for the house side as described in Patent Literature 1, it is necessary to install an expensive rechargeable battery in addition to that in the electric vehicle.
The present invention was proposed in the light of the aforementioned circumstances, and an object of the present invention is to provide an electricity management apparatus, an electricity management program, and an electricity distribution system which are capable of charging an electric vehicle substantially without using grid power.